THE HEMOFLAGELLATES 



67 



than in adults, and also occurs com- 

 monly in dogs. It is transmitted by 

 P. cliiiieiisis and P. 



sergeiiti. 



4. Mediterranean or infantile kala-azar 

 is found in countries of the Mediter- 

 ranean basin including southern 

 Europe and in parts of tropical Africa. 

 Dogs are much more commonly in- 

 fected than man, and 90% of the af- 

 fected people are children less than 5 

 years old. The incidence in dogs may 

 reach 20% in some countries, and in- 

 fection rates as high as 40% have been 

 reported in Greece and Samarkand. 

 Even in such countries, the infection 

 rate in children is only 1 to 2%. 

 Mediterranean kala-azar is transmitted 

 principally by P. perniciosus and P. 

 major. 



5. South American kala-azar is found 

 from Mexico to northern Argentina. 



It attacks human beings of all ages and 

 also occurs in dogs and cats. In a 

 monographic review of visceral leish- 

 maniosis in Brazil, Da Silva (1957) 

 stated that it is endemic and at times 

 epidemic in certain areas, that it is 

 transmitted by Plilebotonius longipal- 

 pis from a natural reservoir host such 

 as the dog, and that it occurs mostly 

 among persons with a low economic 

 status and particularly among the 

 children of that group. According to 

 Deane (1956, 1958), the dog is the 

 principal urban reservoir and the most 

 important source of human infection, 

 while the "bush-dog" {Lycalopex vet- 

 uliis) is probably the principal rural 

 one. The disease is also transmitted 

 by P. iiitermedius. 



Two cases of visceral leishmaniosis 

 have been reported in dogs in the United 

 States, one in Alabama by Thorson et al. 

 (1955) and the other in Washington, D. C. 

 by Gleiser, Thiel and Cashell (1957). 

 Both dogs had been imported into this 

 country from Greece. 



Of the five types of visceral leish- 

 maniosis, the Mediterranean, Chinese 

 and South American are zoonoses while 

 the Indian and Sudanese are not. The 



reasons for this are not clear, since dogs 

 can be infected experimentally with the 

 Indian and Sudanese denies of L. cloiiovani. 

 Adler and Theodor suggested that it may 

 be because the Mediterranean type is trans- 

 mitted by sandfly bites whereas the Indian 

 type is transmitted when the sandfly is 

 crushed on the skin. Since dogs and infants 

 are not good flyslappers, they are not so 

 likely to get Indian kala-azar. 



Pathogenesis : Kala-azar is an im- 

 portant and highly fatal disease of man, 

 particularly in India. After an incubation 

 period of several months, it starts with an 

 irregular fever lasting weeks to months. 

 The spleen and liver hypertrophy. In ad- 

 vanced cases, there is ulceration of the 

 digestive tract (mouth, nose, large intes- 

 tine) resulting in diarrhea, and ulceration 

 of the skin. There is great emaciation, 

 but the abdomen is swollen. In untreated 

 cases, the mortality is 75 to 95%, being a 

 little higher in adults than in infants. 

 Death occurs in a few weeks to several 

 years, often resulting from intercurrent 

 disease. In treated cases, 85 to 95% re- 

 cover. Following recovery, whitish spots 

 which develop into lentil-sized nodules may 

 appear in the skin, particularly of the face 

 and neck. This condition is known as post- 

 kala-azar dermal leishmanoid. 



Mediterranean kala-azar in children 

 is similar to the above, but the disease 

 usually runs a shorter course. 



Kala-azar is essentially a reticulo- 

 endotheliosis. The reticulo-endothelial 

 cells are increased in number and invaded 

 by the parasites. The cut surface of the 

 enormously enlarged spleen is congested, 

 purple or brown, with prominent Malpig- 

 hian corpuscles. The liver is enlarged 

 and there is fatty infiltration of the Kupf- 

 fer cells. The macrophages, myelocytes 

 and neutrophiles of the bone marrow are 

 filled with parasites. The lymph nodes 

 are usually enlarged and the intestinal 

 submucosa is infiltrated with macrophages 

 filled with parasites; these are especially 

 numerous around the Peyer's patches. In- 

 testinal ulceration, if present, is usually 

 a secondary condition. There is progres- 

 sive leucopenia accompanied by monocytosis. 



